1. Field
Embodiments relate to an organic light-emitting diode.
2. Description of the Related Art
Organic light-emitting diodes (OLEDs), which are self-emitting diodes, have advantages such as wide viewing angles, excellent contrast, quick response, high brightness, excellent driving voltage characteristics, and may provide multicolored images.
A typical diode has a structure including a substrate, an anode formed on the substrate, and a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and a cathode that are sequentially stacked on the substrate. The HTL, the EML, and the ETL may be organic thin films formed of organic compounds.
An operating principle of an OLED having the above-described structure is as follows.
When a voltage is applied between the anode and the cathode, holes injected from the anode move to the EML via the HTL, and electrons injected from the cathode move to the EML via the ETL. Carriers such as the holes and electrons recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted.